Wire forming machine

ABSTRACT

A wire forming die for link fencing comprising a cylinder with a helical slot cut through it of which the inner edges of the slot are relieved to prevent damage to wire formed by the die.

United States Patent Scott [54] WIREFORMING MACHINE [72] Inventor: Herbert W. Scott, Burnaby, British Columbia, Canada [73] Assignee: Gilbey Equipment Ltd., West Vancouver,

Province of British Columbia, Canada [22] Filed: Sept. 1 l, 1969 21 Appl. No.: 858,569

[52] US. Cl ..140/92.94

[51] ..B21f 21/00, B21f45/O0 [58] Field ofSearch ..72/142, 145; 140/92.7,92.93, 140/9294, 90, 147

[56] References Cited- UNITED STATES PATENTS 1,228,031 5/1917 Kriesel 140/90 2,696,746 12/1954 Hoffman et al.. 140/147 3,008,497 1 1/1961 Bergandi ..140/92.94

[451 May 23, 1972 2,573,198 10/1951 Hoffman et a1 ..140/147 3,029,845 4/1962 Egedal 140/147 3,264,855 8/1966 Turbett 140/147 R26,929 6/ l 970 Ostermeier 140/9294 2,112,991 4/1938 Madden 140/9293 2,023,652 12/1935 Valle 140/927 2,420,512 5/1947 Woller 140/927 3,520,334 7/1970 Mueller 140/9294 1,259,378 3/1918 Doring ..l40/92.7

Primary ExaminerCharles W. Lanham Assistant Examiner-13. M. Combs Attorney-Fetherstonhaugh & Co.

[ ABSTRACT A wire forming die for link fencing comprising a cylinder with a helical slot cut through it of which the inner edges of the slot are relieved to prevent damage to wire formed by the die.

2 Claims, 3 Drawing Figures PATENTED MAY 23 I972 HERBERT W. SCOTT ATTORNYS WIRE FORMING MACHINE This invention is concerned with a wire forming machine and in particular with a machine for forming wire for use in wire link fencing.

Machines for forming wire for use in link fencing comprise a cylindrical die having a helical slot cut in it and a blade of diameter substantially similar to the inner diameter of the die and adapted to rotate within the die so that as wire is drawn through the die, the rotating blade kinks it by pressing in into the slot. From the die the wire is passed to an automatic machine at which it is linked to a preceding course, severed and secured to that course.

Existing equipment has been generally effective for forming galvanized wire for fencing, but when it is required to use plastic coated wires, there has been a substantial drawback in that during the passage of the wire through the die, the plastic coating has been cut. This problem, while it is clearly more pronounced with a plastic coated wire, also exists with galvanized or other treated wire. The problem has existed over many years and until the present invention, has found no satisfactory answer.

BRIEF SUMMARY OF THE INVENTION It has been discovered that by relieving the inner edges of the helical slot in the die, this problem can be overcome. It seems that the tearing results from the sharp comer between the slot and the inner cylindrical surface of the die.

DESCRIPTION OF THE FIGURES OF THE DRAWINGS An embodiment of the invention is illustrated in the accompanying drawings, in which,

FIG. 1 is an isometric view of a wire forming die according to this invention,

FIG. 2 is an end view of the die in FIG. 1, and

FIG. 3 is a half section on the line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, a cylindrical die has a blade 11 freely mounted therein and extending longitudinally through the center thereof. The blade is adapted to rotate within the die so that its edges lie close to the inner surface of the die. This can be seen particularly in FIG. 2.

A helical slot 12 is formed in and through the cylindrical wall forming die 10. This slot usually extends from end to end of the die.

When in use, the cylinder or cylindrical die 10 is held against rotation, while blade 11 is mounted in a chuck, not shown, at one end of the die and which rotates the blade within the cylinder. As is customary, the fence wirre enters the die from the side through slot 12 near one end of the die and is of the die blade, as viewed in FIG. 1, it is formed, in known manner, into link fencing.

In the past, the edges defining the slot 12 in the die have been cut square to the axis of the die and it has been discovered that it is this feature which has resulted in tearing of the plastic coating of the wire or in scraping and damaging the wire itself at the formed kinks, even if the wire be bare. According to this invention, it is proposed that the inner corners of the slot be relieved as can be seen in FIG. 3 so that during the rotation of the blade 11, the wire kinks bear against the relieved edges 13 of the slot and are moved along the blade by the pressure of the relieved edges without damage to the wire or its plastic coating.

In particular, the inner edge 13 of the slot is usually chamfered to about 12 to 15 to the perpendicular from the axis of cylinder 10 and is varied according to the hardness of the plastic coating of the wire. The precise angle at which the chamfering is effected is determined empirically, but will usually lie in the range 9 to 17.

It has been found that the die according to this invention is one which effectively holds the problem of cutting and tearing the plastic coating of kinked wire used in forming link fencing.

What I claim is:

l. A die for forming coated wire for use in link fencing without damaging the coat of the wire, comprising a tube of circular cross section having a longitudinal helical slot formed in and extending through the wall thereof, said slot having spaced-apart inner edges extending from end to end thereof and chamfered away from each other at an angle to the perpendicular from the longitudinal axis of the tube, and a blade fitting in and extending longitudinally of the tube centrally thereof, said blade being mounted for rotation within the tube and having longitudinally extending edges close to the inner surface of the tube, whereby a wire entering the tube through said slot is wound around the blade during rotation of the latter, portions of said wire bent around the edges of the blade during rotation of the latter extending into the spiral slot and being moved longitudinally of the tube by the pressure of the chamfered inner edges of the slot without damage to the coating of the wire.

2. A die as claimed in claim 1 in which said inner edges of the spiral slot are chamfered to about 12 to 17 to said perpendicular from the longitudinal axis of the tube. 

1. A die for forming coated wire for use in link fencing without damaging the coat of the wire, comprising a tube of circular cross section having a longitudinal helical slot formed in and extending through the wall thereof, said slot having spaced-apart inner edges extending from end to end thereof and chamfered away from each other at an angle to the perpendicular from the longitudinal axis of the tube, and a blade fitting in and extending longitudinally of the tube centrally thereof, said blade being mounted for rotation within the tube and having longitudinally extending edges close to the inner surface of the tube, whereby a wire entering the tube through said slot is wound around the blade during rotation of the latter, portions of said wire bent around the edges of the blade during rotation of the latter extending into the spiral slot and being moved longitudinally of the tube by the pressure of the chamfered inner edges of the slot without damage to the coating of the wire.
 2. A die as claimed in claim 1 in which said inner edges of the spiral slot are chamfered to about 12* to 17* to said perpendicular from the longitudinal axis of the tube. 